This invention relates generally to an electrical connector and, more particularly, to a zero insertion force electrical connector having cam means therein for actuating the contacts out of engagement with conductors on an electrical component.
It is well known in the art that substantial force is required to insert a printed circuit board into a connector having a large number of spring contacts therein due to the resilient engaging force of the contacts with the edge of the board. As the number of contacts is increased in a connector, the amount of force required to insert the printed circuit board into the connector, or to withdraw it from the connector, may become excessive for practical use. In addition, the direct insertion of boards into connectors having spring contacts therein results in a wiping action occurring between the contacts and the pads on the edge of the board, which causes excessive wear of the pads over lengthy periods of use of the connector. It is, therefore, a common practice in the art to provide a zero insertion force printed circuit board connector in which the contacts are mounted so that they are out of the path of movement of the board when it is inserted into the connector whereby no resistance is encountered upon inserting the board thereinto. Thereafter the contacts are cam actuated into engagement with the pads on the edge of the board. When it is desired to remove the board from the connector, the cam actuation mechanism is released so that the contacts are no longer frictionally engaging the pads on the board, thus allowing the board to be freely removed from the connector. U.S. Pat. No. 3,526,869 discloses a zero force printed circuit board connector in which a rotatable cam pushes a longitudinally movable slide cam element that cams the contacts into engagement with the pads on a printed circuit board inserted into the connector. U.S. Pat. No. 3,478,301 discloses a zero force printed circuit board connector in which the board actuates cam blocks in the connector which in turn cam the contacts into engagement with the board when the board is inserted into the connector. It is also known in the art to provide a zero force printed circuit board connector in which a movable cam on the connector housing acts directly upon the contacts to actuate them. Examples of these connectors are found in the following U.S. Pat. Nos. 3,475,717; 3,329,926; and 3,568,134.
U.S. Pat. No. 3,818,419 to Crane discloses a zero insertion force printed circuit board connector in which separate spring elements are mounted in the connector housing for resiliently urging two rows of contacts into engagement with a printed circuit board mounted in a central slot in the housing. A cam actuator is provided for retracting the contacts away from the printed circuit board so that the board may be withdrawn and inserted into the connector housing with zero insertion force. Thus, in contrast to the other connectors discussed herein, in the Crane connector cam actuation of the contacts opens the contacts rather than closes the contacts.
The general principles discussed above with respect to zero insertion force electrical connectors has also been applied to other forms of electrical connectors in which individual electrical contacts on an electrical component are inserted into a connector housing having cam actuated contacts. The purpose of the present invention is to provide a cam actuator zero insertion force connector in which actuation of the contacts serves to open contacts in a manner similar to that disclosed in the aforementioned Crane patent, however, with a significantly different contact shifting arrangement which allows the contacts to be actuated with lower force.